What pedal system do you have? Are your shoes two-bolt, three or either, and how confident would you be about being able to switch pedal systems?
Look cleats won't take much mud at all. It'll dig out easily with a stick, but that's time you don't want to waste in a race (and you may not have a clean place to do it without putting one foot down again to get back on). That's the only system I know anything about. Some people put Eggbeaters on their road bikes for touring.
Speed comes from what you put behind you. - Judi Ketteler